[systemd-devel] Again, why this strange behavior implied by "auto" in fstab ?

[Franck Bui]

On 01/25/2018 02:27 PM, Colin Guthrie wrote:
>> Initially "noauto" is interpreted only (?) by "mount -a" which was done
>> during boot and can still be re-played later by admin. But in the later
>> case the command is *initiated* by him so there's no magic here.
>>
>> systemd redefined this though: "auto" is equivalent to "run 'mount -a'
>> automatically when a backend device appears on udev's radar" which is
>> totally different. And it's the default: if neither "noauto" nor "auto"
>> is specified then the redefined "auto" is assumed.
>>
>> The proposed change keeps the old default behavior: if neither "auto"
>> nor "noauto" is specified, do the equivalent of "mount -a" during boot only.
>>

[...]

> 
> Isn't the whole "mount -a during boot" a fundamentally fuzzy concept? I
> mean, "in the past" this only worked because there were artificial
> delays introduced to make sure all devices were probably available
> before trying to mount them.
> 

Sorry I was probably not clear: by "do the equivalent of "mount -a"
during boot only" I meant to mount fs listed in fstab  (without
"noauto")  the way it's done currently by systemd during boot.

During boot there shouldn't be any changes. The behavior change happens
later if neither "auto" nor "noauto" is specified: by default do not try
to automagically mount filesystems.